1. Field of the Invention
Among other things, the present invention is related to conveyor belts having a flexible strip or stratum of one or more rare earth magnetic compositions embedded therein. Belts of the current invention are particularly useful in the materials handling arts. Stratum can run the entire length of the belt or sections of the flexible permanent magnetic composition can be embedded within the belt. One or more belt stretch limiting members can be positioned proximate the flexible magnetic stratum. Stators in combination with the flexible strip induce magnetic flux for advancing the conveyor belts.
2. Description of the Previous Art
1) U.S. Pat. No. 5,172,803-Lewin, discloses an endless conveyor belt. Endless belt (2) is spanned over downstream and upstream rollers (33) and (34). Belt (2) has an inner surface (10) provided at each of the reinforced zones (6), (7) and (8) with ridge (9) in which is imbedded permanent magnet (5). Under each magnet (5) is a respective stator (4) that can be energized by alternating current. Lewin also teaches embedding rectangular, flat, cylindrical, ridged, particulate, meshed and powdered permanent magnets into ridge (9) and or flat permanent magnets into ridge (58). According to the '803 Patent, the permanent magnets are fixed to the linear surface of the belt in combination with a juxtaposed stator to form a linear motor for advancing his upper stretch downstream.
2) U.S. Pat. No. 2,655,195-Curtis enables a rubberized magnetic conveyor belt. The '195 Patent's flexible resilient rubber-like layers (12) including the Curtis magnetic composition are impregnated into and disposed over layers (11) by frictioning or coating and serve to bond layers (11) into the belt carcass. Multiple layers of the Curtis magnetic composition are required for the Curtis belt to function. And each of the multiple layers of the '195 magnetic composition runs the width and the length of the belt carcass. Importantly, Magnetite is the only magnetic composition disclosed in the '195 Patent.
3) U.S. Pat. No. 3,169,632-Kain and U.S. Pat. No. 3,179,241-Kane-enable a magnetic flexible cable incorporated into the conveyor belt. Each cable is formed from a plurality of twisted wires. The Kain magnet is mounted in a trough underneath the conveyor belt.
4) U.S. Pat. No. 5,408,935-Matsui, et al., teaches a transportation system utilizing magnetic belt propulsion. The magnet belt conveyor unit (13) uses driving wheel (d) and driven wheel (i) and an endless magnetic belt (1) having a plurality of split magnets enclosed in a yoke extended around the wheels (d) and (i). The split magnets are adapted to be magnetically attracted to the sides of rail (10).
5) U.S. Pat. No. 4,623,061-Pentith enables a belt conveyor. Pentith mounts magnetic blocks (50) to inner face of his belt (14). The blocks (50) are arranged in rows and spaced longitudinally of the belt (14). Recesses (51) are provided between the blocks for ropes (23).
6) U.S. Pat. No. 4,337,598-Barth, et al. discloses an endless belt with automatic steering control. The '598 belt (12) is provided with magnetic sections (26) and (28) which are used in conjunction with magnetic sensors (22) and (24) to track the lateral movement of the belt (12).
7) U.S. Pat. No. 4,892,186-Frei enables a clock conveyor provided with a plurality of entrainment members. Entrainment member (42) can be provided with permanent magnet (51) or soft magnetic plate member (56) to coact with reinforced inserts (17) of belt member (16) or magnetic ledge member (57). The combination of motor (22), sprocket (26), shaft (21) and power take off (23) rather than induction drive the Frei clock conveyor.
8) U.S. Pat. No. 6,298,016 B1-Maeder, et al. discloses a conveyor device. Maeder arranges a flux-conducting member (5) on the first side of guide rail (1). The member (5) consists of parts (5a) and (5b) of the permanent magnet (4). The '016 Patent discloses that a ferromagnetic guide is fixed to the guiding rail while the transport is composed of aluminum or plastic. Flux-conducting member (5) includes magnet (4) with flux conducting parts (5a) and (5b) which in combination with air gap (8a) and flux conducting parts (3c) form the magnetic circuit (8). Maeder, et al. is silent regarding the use of any conveying belt.
9) U.S. Pat. No. 5,147,029-Wadell enables an electromagnetically driven conveyor. Among other things, the Wadell conveyor requires an endless enclosure (10) surrounded by electromagnetic drives (20) and (21). The '029 Patent mandates that the carrier units (22) transport the load. Wadell also teaches that his invention advantageously occupies less space than required by belt conveyors.
10) U.S. Pat. No. 6,607,073 B2-Buchi, et al. discloses a conveyor system. The Buchi permanent magnets (12) are iron magnets. As shown in FIGS. 4 and 5, rotating drive belts (20) carry alternatingly arranged permanent magnets (12). Buchi teaches that the permanent magnets (12) are aligned in rows (11) and that the rows of magnets can be arranged either or the edge or surface of drive belt (20). The '073 Patent is silent regarding any embedment of any magnet inside any belt.
11) U.S. Pat. No. 4,823,939-Langhans, et al. enables a curved path chain conveyor. The '939 Patent's hinged plate links (3) slide along a plastic track (2) having a magnetic strip (6) embedded therein. Langhans ferromagnetic strip (6) is a combination of magnetic power and plastic. Additional ferromagnetic material is incorporated into plastic track (2).
12) U.S. Pat. No. 6,528,908 B1-Lee enables an induction drive for an induction driven conveyor that includes a virtual continuous magnetic body. Lee's virtual continuous magnetic body (150) includes a plurality of pivotable magnets (190, 192, 194, 196, 198, etc.) attached to the roller engaging side (132) of nonmagnetic endless conveyor belt (130). The '908 Patent is silent regarding the embedment of magnetic material inside the Lee conveyor belt (130).
13) U.S. Pat. No. 3,620,357-Folkes teaches a belt conveyor for passengers. The '357 Patent's belt is supported by magnetic repulsion. Magnetization is such that polarity of outer surface of layer (15) and the outer surface of support layer (17) are the same. Thus, in use, there is a distributed upward thrust on the belt. Primarily, Folkes utilizes barium ferrite for his magnetizable material distributed in his belt, but strontium as well as lead ferrite also are functional. Folkes does not embed his ferrimagnetic compound inside the belt (10).
14) U.S. Pat. No. 4,315,568-Mojden discloses a magnetic rail arrangement (14) and a belt (16). The '568 Patent is silent regarding the composition of the Mojden belt (16). Moreover, the permanent magnets (48) and (52) are confined in a U-shaped channel (56) of the '568 magnetic rail (14).
15) U.S. Pat. No. 6,510,941 B2-Schermutzki, et al. enables a device for sealing lateral edge areas of an endless conveyor belt. Schermutzki practices an endless steel belt (1). Permanent magnets (8) are placed with the seal arrangements (7) which are positioned beneath endless steel belt (1). The '941 Patent is silent regarding embedment of any magnets with the endless steel belt (1).
16) U.S. Pat. No. 6,250,474 B1-Howell enables an eddy current magnetic separator for separating nonferrous from ferrous materials. Howell utilizes a non magnetic two-ply poly-rubber or polyurethane belt (10). The '474 Patent is silent regarding embedment of any magnets with the belt (10).
17) U.S. Pat. No. 4,864,170-Eguchi teaches a moving coil linear motor. A bobbin is moved about yokes by the energizing coil. The '170 Patent does not disclose any conveyor belt.
18) U.S. Pat. No. 2,684,753-Kolbe, et. al., enables a magnetic drive for conveyor belts. Each of the drive units (16) includes traction belt (20) that is guided over end rollers (22). One of the rollers (22) receives pulley belt (24) which is directed by pulley (26) that is driven by conventional electric motor (24) connected to standard gear reducer (30). Disposed below each roller (34) is the electromagnetic roll (38) wound about an armature curved to conform with roller (34). Kolbe practices a steel conveyor belt (10) and is silent regarding embedment of any magnets within the belt.
19) U.S. Pat. No. 2,873,843-Wilson discloses a conveyor for moving ferromagnetic license plates. Magnets (32) are secured to the outer surface of inner belt (15) while outer belt (12) is provided with apertures (24). Drive motor (40) turns drive shaft (42) of pulley (26) which rotates inner conveyor (14). When Wilson's magnets (32) contact the surface of the license plates, the license plates are held on the conveyor via magnetic attraction.
20) U.S. Pat. No. 4,643,298-Wallaart enables a magnetic bend for a chain conveyor. Wallaart's base includes two upright legs (2 & 3) that form the rails for the conveyor chain. Permanent magnets (7) are inserted into pockets (13) are formed on the underneath side of legs (2&3). Compressible plastic or rubber (8) between the closure strip (10) and magnet (7) ensure the magnets in pockets (13) are pushed upwards in the bend segment to enable the magnets to exert maximum force of attraction on the chain links (4).
21) U.S. Pat. No. 5,890,583-Garbagnati discloses a magnetic curve for a chain conveyor. Curve (10) includes base (11) and slide portion (12) to which chain conveyor (13) is fastened. Operation of the curve is accomplished by attaching ferromagnets (17) to guide (12) with screws (18).
22) U.S. Pat. No. 5,295,568-Saito, et. al., enables a passenger conveyor. Generally, the conveyor's treadboards move horizontally, but the conveyor can also be utilized as an inclined escalator. Regardless of which Saito embodiment is selected, the flattened linear motor's stators and moving members are positioned horizontally between the advance and return travel paths of the treadboards. Additionally, the '568 Patent teaches that moving member (12) is composed of a nonmagnetic conductor such as aluminum and copper, or a nonmagnetic conductor laminated on the surface of the magnetic material. Moving members (12) are fixed securely to reinforcement member (7B) mounted on the reverse side of treadboard (5). Stators (13) are supported by horizontal members (3) of frame (1) so as to be opposed to moving members (12a & 12b). Energizing stators (13) apply driving force to moving members (12) to move treadboards (5) along advance (4U) and return (4D) guide rails. Saito is silent regarding embedding of any magnetic composition with a belt.
23) U.S. Pat. No. 3,788,447-Stephanoff describes a linear motor conveyor. Stephanoff's guide track (20) includes two halves that are spaced apart to define a slot (40) therebetween. Except for the curve from upper transport run (12a) to lower return run (12b), support surfaces (30 & 32) of guide (20) are horizontal. Vertical stem (18) of conveyor segment (16) is conducting non magnetic copper or aluminum so that a propulsive force will be generated on stem (18) by the traveling field in stators (62). Stators (62) are located on both sides of slot (40) or a laminated core (74) is mounted in guide (20) to provide the return path for electromagnetic flux. Propulsive force in registration with the linear motor stators causes the entire conveyor to circulate around the guide.
24) U.S. Pat. No. 5,027,942-Wallaart teaches a hinged chain conveyor. Rails (3) and (4) have permanent magnets (9) and (10) inserted into at least the bend sections of the rails. The '942 Patent is silent regarding a conveyor belt.
25) U.S. Pat. No. 5,165,527-Garbagnati enables a chain conveyor that includes a magnetizable chain. Magnets (19) are inserted into grooves (15 & 16) of shoulders (11 & 12) of guide track (10) to assist in controlling ferromagnetic chain (14) as the chain moves through bends of the conveyor. The '527 Patent is silent regarding a conveyor belt.
26) U.S. Pat. No. 5,199,551-Wallaart, et. al., discloses a bend segment for a chain conveyor having a plurality of links (4). Wallaart's permanent magnets (8) are arranged in chambers of plastic bend segment. The '551 Patent is silent regarding a conveyor belt.
27) U.S. Pat. No. 5,298,804-Ecker, et. al., enables a curved conveyor belt with supporting frame devoid of belt band rollers. On the opposite side of stator (12), guide ducts (10 & 11) include recess (14) through which running wheel carrier (15) grasps carrying bar (16) and wheels (25 & 26). Wheel carrier (15) is connected to side edges (18 & 19) of belt band (2). Drive is applied via linear motor system (4) that includes stator (12) and magnet (23) that is integrated with crossbar (22) of carrying spar (16).
28) U.S. Pat. No. 3,426,887-Ward, et. al., among other things, discloses the use of introducing a metal strip or applying metallic particulars to the lateral edges of a nonmetallic conveyor belt. The combination of the coil and the ferrous metallic edge forms a type of the Ward linear induction motor. The '887 Patent is silent regarding the embedment of any magnetic composition within conveyor belt (14).
29) U.S. Pat. No. 4,981,208-Jones enables a magnetic spiral conveyor system. Among other things, Jones teaches embedding permanent magnets (32) into the exposed edge of module (28) which contacts the driving bars (26) of the system. In this manner, frictional contact between the conveyor belt and the driving bars is increased. Jones is silent regarding the use of any strip of magnetic composition embedded into the belt (12).
30) U.S. Pat. No. 6,216,852-David discloses a conveyor belt with a lower reinforcing layer. The David conveyor belt (10) has an internal stretch limiting means (76) in the lateral center of the intermediate body section (48). The stretch limiting member is vulcanized into the David conveyor belt (10).
31) U.S. Pat. No. 5,004,098-Marshall enables a conveyor belt. Stretch limiting member (28) is vulcanized into the belt (10′). The Marshall stretch limiter (28) is limited only to the central portion of belt (10′).